A. Field of the Invention
This invention relates to a temperature sensor which is adapted for use in fluid pressure systems such as pressurized air systems for generating alarm signals in response to increase in ambient air or other gas temperature above a determined level.
B. Description of the Prior Art
It is desirable to have temperature sensors of the foregoing type which have a quick response time to sudden increases in temperature which would indicate a fire. In certain instances it is desirable to have a fluid-actuated system rather than an electrical system in certain installations. However, the fluid system, to be successful, must approach the response of electrical or electronic-type systems.
Heretofore, fusible metal temperature sensors have been used consisting of a short brass pipe plug with a small hole therethrough which is filled with a controlled melting-point solder. Plugs of this type are normally used with temperature-sensing systems often used for fire detection, such systems consisting of a long tube header closed at the far end and connected to a source of fluid pressure on the near end. Spaced along the header are a series of T-fittings with one of the plug sensors screwed into the branch of each T to form a pressure-tight system. Sufficient heat near any one of the sensor plugs will melt the solder and release fluid pressure, the loss of which is used to trigger an alarm or other action. Systems of this type have the drawback of being relatively slow in response time to the sudden increase in temperature which would indicate a fire. Accordingly, there has developed a need for a fire detection system which can be used in certain installations where it is undesirable or impractical to have an electrical or electronic system, yet which will respond with equal quickness to such systems.